Liquid fuel injection apparatus for internal combustion engines



Oct. 4, 1938. f M.l A. LAURET Filed March 24, 1936 LIQUID FUEL'INJECTIQN APPARATUS FOR INTERNAL COMBUSTION ENGINES INVENTOR. Marin ndlvjzalg' BY l( j WY ATTORNEYIS f A/ Wi f a Patented Oct.' 4, 1938 PATENT OFFICE LIQUID 'FUEL INJECTION AIPARATUS IOR INTERNAL COMBUSTION ENGINES Marin Andr Lauret, Neuilly/Seine, France Application March 24, 1936, Serial No. 70,601

4 claims. (c1. 12a-139) j The present invention relates to improvements in fuel injecting pumps for vaporizing the petrol either in the engine cylinder or preferably 'in each inlet conduit before passingpthe inlet valve and during the suction of the air, and it is'particularly Vapplicable to internal combustion engines,fe`. g., aviation motors.

In apparatus of this type, it is difficult, in view of the fluidity of the petrol, -to maintain tight joints and to insure correct lubrication oi the parts oi' the ing of the piston. Furthermore, it is diiilcult to obtain a delivery of petrol exactly measured and appropriate to the quantity of air drawn into the cylinder either on the ground or when flying at high altitudes.

According to this invention. fuel injection apparatus ofthe type in which pumps deliver liquid fuel to a zone where it is vaporized by the air utilized to support combustion is characterized by the pumps being controlled by a single cam member driven at a speed half the speed of the motor.

An important feature of this inventionis that each petrol pump acts also as a lubricating pump,

the oil being supplied under pressure through' conduits with suitable valves anddelivered into the appropriate lpart of the pump at a pressure corresponding to `that of the liquid fuel in such manner as to -form around pistons of the pumps, a lfilm of oil preventing any infiltration of the liquid fuel into undesired parts of the engine.

It is preferred to arrangerall of the injecting pumps (the number of which is equal to that of the cylinders of the motor), in a circle in a single` apparatus about a driving shaft and parallel thereto, and to control the pistons of the pumps positively by a single cam mounted on the said shaft. i

Other important characteristics relate to the regulation of the injected supply which may, for example, be effected by the adjustment of the point' of closing of an admission valve of each pump, thus causing the quantity of fuel delivered into the admission conduit to vary depending on how earlyV in the pressure stroke the valve is closed. Whatever may be the methodemployed the control is preferably produced automatically y y barometric devices of suitable number vand character.

In order that this invention-mayA be clearly understood and readily carried into effect, one sheet 'of drawing isappended hereto illustrating embodiments thereof, and wherein:

Figure 1 is a view in vertical section of a multipleA pump with nine cylinders; Q

pump so as to avoid wear and seiz-l -there is no lateral reaction Figure 2 is a detail sectional view of an elementl of Figure 1; f

Figure 3 is a View in section taken on line 3--3 of Figure 1 looking in the direction of the arrows, showing the connection between the lubricating 5 oil supply and a pump chamber. V

Referring to Figure 1, the main shaft of the pump is indicated by the reference numeral I and this shaft is preferably -arranged vertically and driven at half the speed of the' motor; the pumps l0 are arranged around this shaft to the number of nine.4 The shaft I is nounted with double thrust bearings 3l in such manner as to have no play or displacement longitudinally. On the shaft I is fixed a cam in the form of a helicoidal disc 2 l5 which is received, without play, between pairs of rollers 4 and 4' carried byslides 3 actuating pisn tons 6. The cam'Z is formed in such manner that each piston is moved downwards during threequarters of a revolution of the shaft I, that is, for 20 one and a half revolutions of the motor, and to X cause it to rise duringKone-quarter of a revolution of the shaft I or one-half a revolution of the motor, that is to say, during the suction of the cylinder when thepump injects the petrol.

' Each piston 6 is actuated by the corresponding slide 3 by means of a plate 5 'on which the piston is not clamped but is mounted with lateral play, and without longitudinal play, so lthat in each case of the piston 6. 30 Lubrication is eifected by circular piping 9 which receives, through the conduit Ill, the oil under pressure from the motor. This oil passes through a conduit I I,lifts the Valve I 2 and passes through a conduit I2' into the lubricating chamber 8 of 35 each cylinder. There'are as many conduits II and valves I 2 as there are cylinders. When a piston 6 falls, VAits lower part of larger diameter aspirates theil from the chamber 8 through the conduits 8. 'I'his oil fills the annular space between theY cylinder of larger diameter and the piston when the latter is at the bottom of its stroke, and is delivered by the larger portion of thepiston .when the latter rises. This oil maintains,'between the small cylinder and the petrol 45 and' I5 carries the oil to the upper part of the pump'to lubricate the shaft 26, and from there it drops, lubricating the different members in v| passing through the thrust bearing 31 and the bearing 36.

Each injection pump includes a unilateral automatic delivery valve I6 and an admission valve I1 located above the cylinder and on its axis. The petrol coming from the supply pump passes into the chamber which carries the petrol to an admission valve l1 of each cylinder. Each admission valve is controlled by a tappet 2| accommodated in a chamber 22 and provided with a roller 23 running on an annular cam 24. This cam has a steeper part 4| which successively opens the valves I1. In orderthat there may be no loss of petrolfrom the chamber 22', each tappetv 2| is riveted on to a diaphragm 22 of fabric impervious to petrol and which completely closes the chamber 22. Furthermore, this chamber may be provided with a discharge tube having a cock to evacuate, in case of rupture of the diaphragm, the petrol which may reach the chamber 22' through the valve tappet rods. I'he cam 24 is not driven directly kby the principal shaft I of the pump. This shaft carries, fixed to its upper extremity, a sleeve 2 5 with two vertical grooves, in which can move small conical rollers 28 carried by arms of a ring 21, on which arms are also mounted cylindrical rollers 29 which slide in a helicoidal groove in a sleeve 26 fixed to the cam 24.

Above the cam of the cam plate 24 serving for .the control of the admission valves, is a cover plate 42 surmounted by a bell 34. The interior of this bell communicates at 35 with the admission piping below the throttle. Consequently, the same pressure exists in the bell as in the inlet to the cylinders. In the bell is a barometric device or bellows 32 secured at its upper part by a regulating screw 33l and which controls at its lower part, through a rod 30,.the ring 21, the armsY ing to the pressure in the admission pipe, that is t'o say, according to the density of the air.

The supply from each pump, that is to say, the quantity injected inthe inlet of each cylinder during the` suction period, is determined by construction, sothat the ratio of the weights of air and of petrol should be for example that of 14:1. When the pressure diminishes in the admission pipe and in the bell, either by the closing of the gas throttle or owing to the change of the barometric pressure of the surrounding air, the bellows 32 iengthens and causes the cam 24 controlling the admission valves to rotate. In this way,

vthe closing of these valves is retarded, that is to say, when the pistons 6 have already risen rby a, certain amount and delivered petrol into the chamber 40. If, for example, the pressure inthe The arrangement of the rollers running in the grooves, that of the cam 24 mounted on a ball motion, to finally return to theA crank shaft,

stop, and that of the valve tappets actuated by rollers 23, combine to permit the adjustment of the cam 24 by an extremely small effort which can be,easily supplied by the barometric device 32.

An advantageous feature of the construction of the multiple pump is also its manufacture in six principal parts superposed vertically, which permits convenient machining and easy dismounting and in particular the use of light metals for the parts which are not subjected to stresses, Whilst at the same time for the cylinder heads of the pumps the use of special bronze l insures the proper functioning of the valves. This arrangement also permits easy dismounting of the valves whilst preserving a practical pumping space as reduced as possible.

I claim: y

1.- A fuel supply mechanism comprising a housling having a plurality of ducts'formed therein to supply a liquid fuel under pressure, a plurality of pump means in the housing to subject the fuel to pressure, each of said pumps including a piston, means for actuating the pistons, an enlarged portion on each of the pistons, the housing being formed with cylinders within which the pistons are received, and each of the cylinders being formed with an enlarged portion to receive the enlarged portions ofthe pistons, and means to supply lubricant to the enlarged portions of the housing, a return valve in the housing communicating with the enlarged portions of the cylinders to limit the oil pressure therein, and a spring engaging the valve and serving as the loading means therefor to load the valve to a constant degree, whereby the enlarged portions of the pistons form lubricating pumps to maintain a lm of oil about the pistons to prevent infiltration of the petrol into the source of lubricant.

2.A A fuel supply mechanism comprising a housing having a plurality of pump chambers formed therein'to supply a liquid fuel under pressure, a plurality of pump means in the housing to sub- *ject the fuel to pressure, each of said pumps including a piston, a shaft in the housing driven by the engine in connectionwith which the mechanis'm` is used, a cam on the shaft for actuating the pistons, a fuel delivery chamber in the housing, tappet valves controlling the communication between the fuel delivery chamber and the pump chambers, diaphragms Iforming walls of the fuel delivery chamber to prevent leakage of the fuel therefrom, means to secure the tappets to the diaphragm, and a cam operated by the shaft for actuating the diaphragms.

3. A fuel supply mechanism comprising a hous ing having a plurality of ducts formed therein to supply a liquid fuel under pressure, a plurality of pump means in the housing to subject 'the fuel to pressure, each of said pumps including a piston, a single helicoidal cam disc for actuating the pistons, a pair of rollers for each of the pistons, between which rollers the cam disc is received, sliding guides offset with respect to the axes of the respective pistons and upon which the rollers are mounted, said guides being movable upon an axis parallel to the axis of the cam disc and means to connect the pistons to the respective rollers and guides, whereby lateral reaction of the rollers is prevented vfrom being transmitted to the pistons.

4. A fuel supply mechanism according to claim 2, wherein the cam which actuates the diaphragms is driven by the shaft through a connection including a grooved sleeve on the shaft;

density of the air admitted to the engine, and solid mechanical means received within the sleeves to control the pin connection positively by the means responsive to the variations in density.

I MARIN ANDR LAURET. 

